ForceNet represents atoms as nodes in a GNN and the atomic interactions as edges. The node input features specify the atom's atomic number and other properties (9-dimensional vector adapted from [1]}). Edges in the GNN are constructed from a radius graph of neighboring atoms [2]}, [3]}. Let \(\mathcal {N}_t(c)\)  denote a set of neighboring atoms that are within the cutoff-distance \(c\)  away from the target atom \(t\) . On average an atom has 35 neighbors. A directed edge from source atom \(s\)  to target atom \(t\)  is drawn for \(s \in \mathcal {N}_t(c)\) . Let \(\mathbf {d}_{st} \in \mathbb {R}^3\)  be their relative displacement, i.e., a vector pointing from atom \(s\)  to atom \(t\) .
